Tellurium catalyst and method of selective oxidation



Patented Aug. 31, 1954 UNITED STATES PATENT OFFICE.

TELLURIUM CATALYST AND METHOD OF SELECTIVE OXIDATION William R.Middleton, Wenonah, N. J., assignor to Socony-Vacuum Oil Company,Incorporated, a corporation of New York No Drawing. Application January26, 1951, Serial No. 208,073

Claims.

- filed January 19, 1950, now U. S. Patent No.

2,648,638 in the name of Frederick P. Richter, it has been disclosedthat the activated methyl group or the activated methylene group of anorganic substance can be selectively oxidized in the presence of acatalyst comprising predominantly at least one oxide of tellurium to acarbonyl group. The present invention relates thereto and represents theapplication of the discovery that the addition of Vanadium oxide to thecatalyst disclosed in application Serial No. 139,529 provides animproved catalyst for the reactions disclosed in the earlier filedapplication.

It is to be understood that the phrase gas containing free oxygenincludes elemental oxygen, pure diatomic oxygen, diatomic oxygen dilutedwith an inert gas such as nitrogen, helium, carbon dioxide, thetriatomic oxygen or ozone and It is also to be understood that thecatalysts described hereinafter can be used in the unsupported state orsupported by materials which are inert or materials which are active.The unsupported catalyst can be used in finely divided form suitable forfluid systems wherein the catalyst flows from one part of the system tothe other in a stream of gas or as large particles.

Active supports are those which, like silica gel, per se accelerate theoxidation of olefins to CO, CO2 and H20.

Inert supports are those such as fused alumina (available as TabularAlumina) which per se do not accelerate oxidation reactions.

As described in the co-pending application Serial No. 139,529 manyclasses of compounds having activated methyl or methylene groups can beselectively oxidized to carbonyl compounds.

Broadly illustrative of the classes of compounds which may be oxidizedin this manner and the products obtained are the following equations:

where Z is a monovalent radical having at least one center ofunsaturation such as C 0; a group capable of oxidation to a carbonylgroup, for example a hydroxyl group; CEC; C=C; or the double bond of anaryl group directly adjacent to the methyl or methylene group and R ishydrogen or alkyl or cycloalkyl or aryl or alicyclic or heterocyclic;when R is other than hydrogen it can be substituted by any substituentwhich will survive under the reaction conditions, for example, a phenylgroup, a halogen, a nitro group and the like.

0 II (c) AI'CHzR T ArCR 1120 e ll 0 ll ArCCHa ArCOHO 1120 where Ar is anaryl radical substituted or unsubstituted.

(a) RCHzCHaOH T RCOHO 21120 where R is hydrogen, alkyl, cycloalkyl,aryl, heterocyclic and Where other than hydrogen may be substituted byany substituent which will survive under the reaction conditions, forexample, a phenyl group, a halogen, a nitro group and the like.

It will be recognized that in the foregoing (3) Compounds containing acenter of unsaturation such as the double bond of an aryl group as anintegral part of an alicyclic ring system directly adjacent a methyl ormethylene group:

mediate of a primary or secondary alcohol and a carboxylic acid.

It has been discovered that the, method of selectively oxidizing theactivated methyl or methylene groups of an organic compound to acarbonyl group with gas containing free oxygen in the presence of acatalyst comprising predominantly at least one oxide of tellurium can beimproved with respect to conversion by incorporating in the telluriumcatalyst at least about 2 mole per cent of at least one oxide ofvanadium.

The promoted or mixed catalysts which have been found capable ofproducing the improved results to which reference has been madehereinbefore can be prepared in accordance with well is added to astirred, preferably concentrated, aqueous solution of telluric acid. Thevanadyl chloride is added to the telluric acid solution in amount toyield a mixture containing about 2 to about 40, preferably about 5 toabout 20, mole per cent of an oxide of vanadium based upon the telluriumoxide.

-When the catalyst is to be used in the unsupported form the mixture ofvanadyl chloride and telluric acid is evaporated to dryness and theresidue ground to the desired particle size.

When the catalyst is to be used in the supported. form theclear greensolution of vanadyl chloride and telluric acid is applied to the supportusing a volume just sufficient to saturate completely the surface andpores of the support material. The wet catalyst and support are thendried at about 110 C. for several hours to remove water and obtainsubstantial hydrolysis of the vanadyl chloride.

Other suitable methods for the preparation of the promoted or mixedvanadium-tellurium catalyst comprising about 2 to about 40, preferablyabout 5 to about 20 mole per cent oxide of vanadium and the balancepredominantly at least one oxide of tellurium may be employed. Forexample, vanadium pentoxide and tellurium dioxide in the proportionsnecessary to afford about 2 to about 4.0, preferably about 5 to about 20mole per cent oxide of vanadium (based upon the tellurium oxide) can bedissolved simultaneously in concentrated aqueous hydrochloric acid toform a mixture of oxychlorides which can then either be hydrolyzed bymoist air or steam to yield the mixed oxides and dried or the solutionof the mixed oxychlorides can be applied to a support and thenhydrolyzed anddried.

Illustrative but not limiting of the present invention are the followingexamples of runs made to demonstrate the improved results obtained withthe novel promoted or mixed catalysts comprisingv or consistingessentially of about 2 to about 40, preferably about 5 to about 20, moleper cent oxide of vanadium and the balance predominantly at least oneoxide of tellurium.

The catalysts employed in Examples I through VII were used with fusedalumina as the support. The supporting material of the catalysts used inExamples VIII through XII was tempered silica gel.

Table I Compound having an activated methyl group established principlesand can be used in the un- Propylene. ported form or in the supported fom- Ratio of gas containing free oxygen (air) to For example, a suitablecatalyst can be prepropylene=3:1.

pared by dissolving vanadium pentoxide Total gas space velocity=4.

(V2O5-1.5 H2O) in a minimum amount of 39 Propylene space velocity=1.

per cent aqueous hydrochloric acid (about 4 Catalyst supportfusedalumina.

Example No I II III IV V VI VII Mole percent V0; 5.0 5.0 5.0 5.0 5.0Gms. Tool/ cc. of support... 10 10 10 10 10 l0 l0 Catalyst Temp. Range,750-752 7524 100 753-4 705 75243 100 Max. obs. Temp. Rise,F 3 2 1 2 l 41 Conversion, Mole percent 4.8 3.8 2.2 3.2 1.9 1.6 0.95

1 Mole percent propylene converted to acrolein per pass.

cc. per gram of oxide). The solution is then heated, say, on a hot waterbath until the oxide is converted to the oxychloride (vanadyl chlorideV0012); this requires about 1 to 1.5 hours. The solution of vanadylchloride thus formed For facility of comparison the mole per cent ofpropylene converted to acrolein per pass and the maximum observedtemperature rise in the catalyst bed for Examples I through VII arepresented in Table II.

Table II Mole Percent Maximum Observed Reaction Conversion TemperatureRise, F. Example No. T erin p 5 Mole Per- 5 Mole Percent V; No cent V0:No

It will b noted that in the reaction temperature range '700-'705 F. thatthe conversion in the presence of mole per cent VOx is about 200 percent of that obtained with an unpromoted tellurium catalyst while themaximum observed temperature rise in the catalyst bed is approximatelythe same. Similarly in the reaction temperature range 750-'l56 F. themole per cent conversion of propylene to acrolein per pass in thpresence of 5 mole per cent VOX is about 250 per cent of that obtainedwith an unprornoted tellurium catalyst while the maximum observedtemperature rise in the catalyst bed of promoted tellurium is only about50 per cent of that observed with an unpromoted tellurium catalyst.

Table III Compound having an activated methyl group- Example No VIII IXX XI XII Mole percent V0; 5 5 5 Gms. TeO/lOO cc. support 10 l0 10 10 10Catalyst Temp, F 696 709 748 707 700 Max. obs. Temp. Rise, F 74 70 12145 Conversion, Mole percent per pass 2 10. 3 8 5 l1. 8 5. 5 5. 6

1 Calculated as TeOz.

. Propylene to acrolein.

It will be noted that in the temperature range 696 to 709 F. the moleper cent conversion of propylene to acrolein with the promoted telluriumcatalyst is about 170 per cent of that obtained with the unpromotedcatalyst while the maximum observed temperature rise per mole percent ofpropylene converted to acrolein is about the same.

The supports can be of the inert type or the active type. Inert supportsare those such as fused alumina which per se do not accelerate oxidationreactions. Active supports are those which, like silica gel, per seaccelerate the oxidation of olefms to C0, C02 and H20. It will beunderstood that when a tellurium" catalyst supported on an activesupport is used, there is a tendency for a greater proportion of thereactant or reactants to be converted to the products of ultimateoxidation. Other materials which may be used for supporting the finelydivided tellurium are silicon carbide aggregate, porous porcelain,alundum and the like.

Reaction temperatures between the normal methyl-1,3-hexadiene,

boiling point and the temperature of decomposition of the organicsubstance to be oxidized can be used. For many reactions temperatures ofabout 200 to about 550 C'. have been found useful but optimumtemperatures will be dependent upon the individual conditionsencountered. Thus, for example, the preferred temperature for theconversion of propylene to acrolein is about 350 C. to about 425 C.while the preferred temperature for the conversion of isobutylene tomethacrolein is about 220 to about 380 C.

While the conversions described hereinbefore were all carried out atatmospheric pressure, any reasonable pressure including sub-atmosphericpressures can be used.

The organic substance to oxidizing gas ratio can be varied over a widerange although it is preferred to use ratios of about 1:1 to about 1:9.

Broadly defined, the substances which can be oxidized with air or othergas containing free.

oxygen in the presence of non-stoichiometric quantities of finelydivided catalyst comprising predominant at least one oxide of tellurium,are those having hydrogen atoms attached to a carbon atom alpha to anunsaturated carbon atom such as in olefins of three or more carbonatoms; isolated diolefins; i. e., diolefins in which there is at leastone methylene or substituted methylene group between the olefiniccarbons; acetylenic hydrocarbons having at least three carbon atoms;conjugated diolefins of more than four carbon atoms; cycloolefins, forexample, cyclopentadiene; aromatic hydrocarbons, such as xylene, methylnaphthalenes, methyl anthracenes and the like, or alpha to a hydroxylgroup, such as ethanol, propanol, pentanol, isopentanol, octanol,octadecanol, octadecenol, ethandiol, propandiol, butylene, glycol,pentylene glycol, octandiol and in general hydrocarbons, substitutedhydrocarbons and primary and secondary alcohols of up to 22 carbonatoms. For example, paraflin wax (18-24 carbon atoms) can behalogenated, dehydrohalogenated to the olefinic form and then oxidized.

Thus, for example, substituted butadiene derivatives, conforming to thegeneral formula,

wherein R and R are alkyl or aryl groups substituted or unsubstitutedcan be oxidized in the manner described hereinbefore and converted tothe corresponding carbonyl compounds.

Thus, for example, 1,3-butadiene, 1,3-pentadiene (alpha-methylbutadiene)l l-pentadiene, 2- methyl1,3-butadiene (isoprene), 1,5-hexadiene(diallyl), 2-methyl-1,4-pentadiene (isodiallyl),2,3-dimethyl-1,3-butadiene (diisopropenyl), 3-

3-methyl-2,4-hexadiene,

benzene,1,2,4 trimethyl ethylbenzene,

oxidized to the corresponding carbonyl 2,7-heptadiene,4-methyl-1,6-heptadiene, 2,5-dimethyl-2,4-hexadiene,3-methyl-1,5-octadiene, 1,4-nonadiene, 3,7-decadiene can be oxidizedwith air in the presence of finely divided catalyst comprisingpredominantly at least one oxide of tellurium at temperatures of about350 to about 550 C. or generally at temperatures at which the diolefinis gaseous but below the cracking temperature of the diolefin to thecorresponding carbonyl compounds.

Illustrative of another group of hydrocarbons which can be oxidized tothe corresponding carbonyl compounds in gaseous phase with pure ordiluted gaseous oxygen in the presence of the tellurium catalyst attemperatures at which the hydrocarbon is gaseous but below the crack-;ing temperature of the hydrocarbon are the following members of theacetylene series: 2- butyne, 2-pentyne, 2-hexyne, 3-hexyne, 4-meth--yl-2 pentyne, 3-heptyne, 5-methyl-2-hexyne,

4,4 dimethyl 2 pentyne, 5 methyl 5 ethyl-B-heptyne, Z-undecyne,6-dodecyne, 2-hexadecyne, 9-octadecyne.

Illustrative of the aromatic hydrocarbons which can be oxidized to thecorresponding carbonyl compounds by air in the presence of the telluriumcatalyst at temperatures between the normal boiling point of thehydrocarbon and the cracking temperature thereof are trimethylbenzene,o-ethyltoluene (l-methyl-2-ethylbenzene) 1-nethyl2-propyl-benzene,1,3-dimethyl- -4-ethylhenzene, tetra-methylbenzene, l-methyl- 4isobutylbenzene, 1,2 dimethyl 4 propylmethyl-3-amylbenzene,1,3-dimethyl4,6-dieth- -ylbenzene, 1 methyl 2 propyl 4 isopropylbenzene,1,3,5-trimethyl-2,a-dimethylbenzene, al-

pha and beta styrene, l-phenyl-l,3-butadiene, linethyll-propenylbenzene,l-phenyl-Z-pentene, dimethyl naphthalene, dimethylanthracene,diimethylphenanthrene or the like.

Illustrative of the cyclo-olefins which can be compounds by air in thepresence of the tellurium catalyst at temperatures between the boilingpoint and the cracking temperature of the cycloolefin arel-methyl-l-cyclobutene, l-methyl-lcyclopentene, 1,2 dimethyl lcyclopentene, 1-

,methyl 2 ethyl 1 cyclopentene, l methyl-2- ropyl-cyclopentene,1,Z-dimethyl-l-cyclohexene,

and 1-ethyl-3-rnethyl-l-cyclohexene.

Illustrative of the organi compounds, having a methyl or methylene groupactivated by the presence or" a hydroxyl group, which can be oxidized tothe corresponding carbonyl compounds by gaseous oxygen (pure ordiluted), ozone and air in the presence of the tellurium catalyst attemperatures between the boiling point of the compound and thetemperature at which said compound cracks or decomposes are thefollowing: glycol, propandiol-l,2; propandiol- 1,3;1,2-dihydroxybuta-ne, L-dihydroxybutane, 2,3-dihydroxyhexane and thelike. Monohydroxy compounds such as the aliphatic alcohols, ethanol,butanol,- propanol, hexanol, octanol and the like can also be oxidizedto the corresponding carbonyl compounds by gaseous oxygen in thepresence of the tellurium catalyst at temperatures between the boilingpoint of the alcohol .and the temperature at which the alcoholdecomposes.

A characteristic of the catalyst disclosed hereinbefore is its capacityto promote the oxidation .of methyl or methylene groups directlyadjacent ,to a center of unsaturation in an organic comll RCH:CH=CHR RCCH=CHR' II RCCHzR' Compounds intermediate between the above reactantsand the products in oxidation state such as, for example, benzylalcohol, allyl alcohol and the like also can be oxidized using thetechnique disclosed hereinbefore. Ethylene can be oxidized to glyoxaland anthracene to anthraquinone as can organic substances which form insitu reactants such as those the oxidation of which has been discussedherein or their intermediate oxidation products through dehydrogenation,dehydration, rearrangement, dehalogenation, dehydrchalogenation andsimilar reactions, for instance, methyl cyclohexadiene, tertiarybutanol, beta-pinene, 2,3-diiodopropane and alpha-bromodiethylketone.

Similarly mixtures of compounds having an activated methyl or methylenegroup with other compounds can be used as well as the pure compound.Thus, for example, the propylene-propane fraction of refinery gascontaining about 52 mole per cent propylene, about 46 mole per centpropane and the balance higher and lower molecular weight alkanes andalkenes can be mixed with air and the propylene oxidized to acrolein inthe presence of a novel catalyst such as has been describedhereinbefore.

I claim:

1. A process for oxidizing a hydrocarbon containing a radical selectedfrom the group consisting of methyl and methylene radicals directlyadjacent to an unsaturated carbon to carbon linkage, whereby saidradical is selectively oxidized to a carbonyl group, which comprisescontacting said hydrocarbon in the vapor state with an oxygen-containinggas in the presence of a catalyst consisting essentially of an oxide oftellurium and about 2 to about 40 mole per cent of an oxide of vanadium.

2. A process for oxidizing a hydrocarbon having at least one unsaturatedcarbon to carbon linkage and containing a radical selected from thegroup consisting of methyl and methylene radicals, said radicals beingadjacent to an un saturated carbon to carbon linkage, which comprisescontacting said hydrocarbon with an oxidizing gas at a temperaturebetween about 200 C. and about 550 C. in the presence of a catalystconsisting essentially of an oxide of tellurium and about 2 to about 40mole per cent of an oxide of vanadium, whereby said radical isselectively oxidized to a carbonyl group.

3. A process for oxidizing an olefinic hydrocarbon containing a radicalin alpha position to a carbon to carbon double bond and selected fromthe group consisting of methyl and methylene radicals, which comprisescontacting said olefinic hydrocarbon in the vapor state with a gascontaining free oxygen in the presence of a catalyst consistingessentially of an oxide of tellurium and about to about 20 mole per centof an oxide of vanadium, whereby said radical is selectively oxidized toa carbonyl group.

4. A process for oxidizing an aromatic hydrocarbon containing a radicalin alpha position to a carbon to carbon double bond and selected fromthe group consisting of methyl and methylene radicals, which comprisescontacting said aromatic hydrocarbon in the vapor state with a gascontaining free oxygen in the presence of a catalyst consistingessentially of an oxide of tellurium and about 2 to about 40 mole percent of an oxide of vanadium, whereby said radical is selectivelyoxidized to a carbonyl group.

5. A process for oxidizing an unsaturated hydrocarbon characterized bythe presence of at least one radical selected from methyl and methylenegroups which are activated by the proximity thereto of an unsaturatedcarbon to carbon linkage, which comprises contacting said compound at atemperature between the normal boiling point and decompositiontemperature thereof with a gas containing free oxygen in the presence ofa catalyst consisting essentially of 10 an oxide of tellurium and about2 to about mole per cent of an oxide of vanadium.

6. A process for selectively oxidizing propylene to acrolein, whichcomprises contacting propylene vapor with an oxygen-containing gas inthe presence of a catalyst consisting essentially of an oxide oftellurium and about 2 to about 40 mole per cent of an oxide of vanadium.

7. A novel catalyst consisting essentially of about 2 to about 40 moleper cent of an oxide of vanadium and an oxide of tellurium.

7. A novel catalyst consisting essentially of about 5 to about 20 mo1eper cent of an oxide of vanadium and an oxide of tellurium.

9. The catalyst described and set forth in claim 7, wherein the catalystis deposited on a silica gel support.

10. The catalyst described and set forth in claim 7, wherein thecatalyst is deposited on a fused alumina support.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 2,383,711 Clark et a1 Aug. 28, 1945 2,530,923 Turk et al. Nov.21, 1950

1. A PROCESS FOR OXIDIZING A HYDROCARBON CONTAINING A RADICAL SELECTEDFROM THE GROUP CONSISTING OF METHYL AND METHYLENE RADICALS DIRECTLYADJACENT TO AN UNSATURATED CARBON TO CARBON LINKAGE, WHEREBY SAIDRADICAL IS SELECTIVELY OXIDIZED TO A CARBONYL GROUP, WHICH COMPRISESCONTACTING SAID HYDROCARBON IN THE VAPOR STATE WITH AN OXYGEN-CONTAININGGAS IN THE PRESENCE OF A CATALYST CONSISTING ESSENTIALLY OF AN OXIDE OFTELLURIUM AND ABOUT 2 TO ABOUT 40 MOLE PER CENT OF AN OXIDE OF VANADIUM.7. A NOVEL CATALYST CONSISTING ESSENTIALLY OF ABOUT 2 TO ABOUT 40 MOLEPER CENT OF AN OXIDE OF VANADIUM AND AN OXIDE OF TELLURIUM.